Gas discharge lamps are used in a wide variety of applications to emit radiation falling within a defined band width. Radiation is emitted by the lamp by capacitively exciting a working gas retained within the lamp with a pair of excitation electrodes diametrically positioned on opposite sides of the lamp. One such gas discharge lamp is described in U.S. Pat. No. 6,646,444, the disclosure of which is incorporated herein by reference. Alternatively, the working gas can be inductively excited. As disclosed in U.S. Pat. No. 6,646,444, a preferred working gas is Krypton.
In order to maintain proper performance of a gas discharge lamp, the working gas needs to remain relatively pure. Contamination of the working gas within the lamp, such as from residual gases remaining within the lamp during manufacture or gradual release of adsorbed gases into the lamp, decreases operability and performance.
It is customary to incorporate a getter into gas discharge lamps in order to reduce or eliminate contamination gases within the lamp. Getters function by chemically combining with or adsorbing contaminant gases, thereby preventing them from interfering with excitation of and emissions from the working gas.
Getters, typically a metal foil such as titanium, are highly susceptible to oxidative degradation if heated while exposed to a high concentration of oxygen such as found in the atmosphere. Unfortunately, typical methods of constructing gas discharge lamps subject the getter incorporated into the lamp to temperatures in excess of 300 to 500° C. while they remain exposed to the atmosphere, resulting in degradation of the getter and loss of both performance and useful lifespan of the lamp.
Accordingly, a substantial need exists for an easy, inexpensive and reliable method of incorporating a getter into a gas discharge lamp without oxidative deactivation of the getter.